<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        img {
            display: block;
            width: 100%;
        }

        li {
            list-style: none;
        }

        ul {
            width: 60%;
            margin: 60px auto;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            border: 1px solid #eeeeee;
            padding: 10px 10px 0;
        }

        li {
            width: calc((100% - 10px * 2) / 3);
            border: 5px solid #eeeeee;
            position: relative;
            margin-bottom: 10px;
        }

        li::before {
            content: "";
            display: block;
            position: absolute;
            bottom: 10px;
            left: 10px;
            width: 20px;
            height: 20px;
            background-image: url("./images/demo1/tu.png");
            background-size: contain;
            z-index: 2;
        }

        ul li:hover {
            &::after {
                content: '';
                width: 100%;
                height: 100%;
                display: block;
                background-color: rgba(119, 119, 119, 0.55);
                position: absolute;
                top: 0;
                z-index: 1;
            }

            &::before {
                background-image: url("./images/demo1/tu2.png");
            }
        }


    </style>
</head>
<body>
<div id="root">
    <ul>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
        <li>
            <img alt="" src="./images/demo1/1.jpg">
        </li>
    </ul>
</div>

</body>
</html>